Polyalkylene glycol esters of ethylene-diaminetetraacetic acid as lubricant dispersants

ABSTRACT

A NEW CLASS OF COMPOUNDS AND A SERIES OF NOVEL LUBRICANT COMPOSITIONS ARE DISCLOSED. POLYALKYLENE GLYCOL-ETHYL ENEDIAMINETETRAACETIC ACID ADDITION COMPOUNDS WHICH ARE USEFUL AS DISPERSANTS IN POLYALKYLENE GLYCOL LUBRICANT FLUIDS AS SLUDGE DISPERSANTS AND LUBRICANT FLUID COMPOSITIONS INCLUDING SUCH COMPOUNDS ARE DESCRIBED.

United States Patent O POLYALKYLENE GLYCOL ESTERS F ETHYLENE-DIAMINETETRAACETIC ACID AS LUBRICANT DISPERSANTS Frederick F. Caserio,Jr., Laguna Beach, and Ting-I Wang,

Fullerton, Calif., assignors to Atlantic Richfield Company,Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Filed Oct.8, 1968, Ser. No. 775,981

Int. Cl. 'C10m 1/32 US. Cl. 252-515 4 Claims ABSTRACT OF THE DISCLOSUREA new class of compounds and a series of novel lubricant compositionsare disclosed. Polyalkylene glycol-ethylenediaminetetraacetic acidaddition compounds which are useful as dispersants in polyalkyleneglycol lubricant fluids as sludge dispersants and lubricant fluidcompositions including such compounds are described.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to chemical compositions and, more particularly to chemicalcompositions useful as lubricating fluid additives and to lubricatingfluid compositions. Still more particularly, this invention relates topolyalkylene glycol-ethylenediaminetetraacetic acid lubricant additivesand lubricant compounds.

Description of the prior art Motor fuel lubricants, such as conventionalautomobile motor oil or oils designed for special applications, e.g.,marine, aircraft and stationary engines, conventionally includeoxidation inhibitors and dispersant additives. Viscosity improvers, etc.are also conventionally added to the basic lubricant fluid to provideparticular characteristics desired in the end lubricating compound.

Many hydrocarbon-based or hydrocarbon-containing additives arecommercially available for use in conventional hydrocarbon lubricatingfluids. It is, of course, essential that any successful additive besoluble in the lubricating fluid at all potential operating or handlingconditions. Long chain aliphatic hydrocarbon substituted succinicacid-amine derivatives have been proposed as dispersant additives forhydrocarbon-based lubricant fluids, see US. Pat. No. 3,172,892, LeSuerand Norman, for example.

A new class of potentially commercially valuable lubricating fluids hasbeen developed, however, in which most known dispersant additives areinsoluble or of limited solubility. It is, accordingly, an object ofthis invention to provide improved dispersant additives fornon-hydrocarbon lubricant fluids.

SUMMARY OF THE INVENTION A new class of synthetic crankcase oils for usein automobile engines, aircraft engines, marine engines, stationaryengines and the like, are described. The basic fluid, in the preferredembodiment, is a doubly end-blocked polypropylene glycol diether polymeridentified hereinafter as Ucon fluid DLB-ZOOE. It has been found thatwhile many oxidation inhibitors useful in petroleum derived hydrocarbonlubricant fluids may be used with the synthetic crankcase oils of thisinvention, none of the dispersant additives previously'known aresufliciently soluble and none are otherwise successful as dispersants inthe synthetic crankcase oil compositions of this invention. It is,accordingly, a principal object of this invention to provide a new andimproved dispersant additive for use in propylene glycol diether polymersynthetic lubricating fluids.

3,562,161 Patented Feb. 9, 1971 Similarly, a principal object of theinvention is to provide improved synthetic lubricant fluids for use ascrankcase oils and as lubricants generally, which comprise polypropyleneglycol diethers, as base fluids and an improved sludge dispersantadditive.

A more specific object of the invention is to provide an improveddispersant additive comprising polyalkyleneglycol-ethylenediaminetetraacetic acid compounds.

An additional and more specific object of the invention is to provide alubricating composition including a polyalkylene glycol dietherlubricant base fluid in combination with a sludge dispersant additivecomprising polyalkylene glycol-ethylenediaminetetraacetic acidcompounds.

A further and more specific object of the invention is to provide aclass of polyalkylene glycol-ethylenediaminetetraacetic acids for use aslubricant additives.

A process for preparing lubricant additives and lubricant fluidsconstitutes an additional and still more specific object of theinvention.

The provision of the specific compounds described hereinafter and thespecific processes for producing these compounds and the describedlubricant fluids constitutes an additional and highly specific, butnon-limiting, object of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The foregoing and additionalobjects are accomplished in general by preparing the desiredpolyalkylene glycolethylenediaminetetraacetic acid (EDTA) compounds andblending the resultant product with a propylene glycol diether polymerlubricating fluid generally of the type identified as Ucon fluidDLB-200E or equivalent.

The dispersant additives of this invention are prepared,

' in general, by refluxing ethylenediaminetetraacetic acid (EDTA) with apolyalkylene glycol at a temperature sufliciently high to initiate thereaction and remove water. A solvent, such as toluene, xylene, etc., maybe used during the refluxing operations, if desired.

The reaction, the formation of the polyalkylene glycol ester of EDTA iscarried out under atmospheric pressure, with or without the addition ofsolvent, at temperature of from about C. to about 300 C., and preferablyin the range of about C. to C. for from about 1 to about 500 hours,preferably from about 10 to about 200 hours.

The process is illustrated by the following specific examples showingthe reaction conditions thereof.

0.1 mole of EDTA and 0.1 mole of a polypropylene glycol ether identifiedas Ucon fluid LB-385, produced by Union Carbide Plastics and ChemicalsDepartment, New York, along with 100 mls. of toluene and 0.005 mole ofsulfosalicyclic acid as a catalyst were introduced into a 500 ml.reaction flask. Ucon LB385 has an apparent specific gravity of 0.995 at20 C., a viscosity index (ASTM D-567) of 144, a viscosity, Sayboltseconds, at 210 F. of 75, at 100 F. of 385, and at 0 F. of 15,000, aviscosity in centistokes at 210 F. of 14.3, at 100 F. of 83.3, and at 0F. of 4,700, with a pour point (ASTM D-97) of 35 F. and a fire point(ASTM D-92) of 500 F. The molecular weight of the poly propylene glycolis about 12004500.

The reaction mixture was refluxed for one hour. At the end of this timethere had been no color change and no H O removal. The temperature wasgradually increased, with distillation of toluene, to 180 C. At thispoint, 1.2 ml. water and 70 ml. toluene were removed. The material wasdark brown with a significant amount of coagulated solids. The solidswere filtered off the solution through a fritted glass 'filter withCelite and rinsed with 50 mls. of toluene. The sample was heated todistill off the excess toluene and was then submerged in an oil noobservable cloudiness or separation. An oxidation inhibitor Oronite 254was added at a 3 percent level.

Dispersant effectiveness was tested by blending the additive to usedUcon DLB-200E obtained from engines used in dynamometer tests. Thedispersant additive product of the aforementioned process was mixed withthe material to be tested in a Waring Blendor for 5 minutes. The samplewas observed for sludge separation, and paper chromatographic spot testswere made to determine dispersant eflectiveness. Data showing therelative eifectiveness of the composition of this invention are given inTable I along with comparative data using other known and experimentaldispersant additives.

TABLE I.DISPERSANT TESTS [Waring Blendor, high speed, 5 minutes] Percentseparation, hrs. settling Percent Code Number cone. Structure 24 240Standard No. 1 100 Used Ucon from chassis dynamometer test on Chevrolet19 72 Standard No. 2. 100 Used Ucon from chassis dynamometer test onFord 4 58 649-29-1 Reaction product of ethylenediaminetetraaeetic acidand Ucon LB-385 polypropylene 0 5 g yeo CH CH I I RO CHzCHz OOCCH2 CHOOO-OH CH O R A n N CHzCHzN R OCH2CH2 OOCCH2 CHzCOO ?H2CH2O- R 1113) 3)1:

649-17-1 5 (012E2 0 C O C CH2)2NCH2CH2N(CH2GO2H)2 3 28 649-7-1 2 C12H23CHO 0 48 1 75 I N-CH2OH2CH2NHZ 01120 O 49-9-1 2 C|zHz3-CHO O C 0-0 H: 501 N(CH2OHzNH) CHzCHzN CH3 CO CO-CH-CmHga CnHzr-CHC 0 (EH: 649-6-1 2 NCHz-CHNH3 649-8-1 2 C zH2aCHC 0 C 0-0112 6 1 18 N(CHzCH2NH)3CH3CHzNCHBOO O0-CHC12H 649-5-1 2 C nHzg-CHC O N-CHzCHgNHCHzCHzNH1 CHsC O 5 Sameas above 2 l8 5 Bls-urninopropyl piperazine 649-16-1 5 C|2H23-("HC 0\/NCHgCHzCHgNONCHzCHzCHzNHz 1 36 CH2 0 O 649-14-1 5 C Hag-GHQ O NCHOHzNHCH CHzNHz 1 16 (31120 0 Plus C12H23-CHCO (JO-CH NCHzCH NHOHzCHzNCHzCO COOHC12 2a 64949-1 5 C1'3H23OHC O NCH2CH2NH2 3 58 5 Maleie acidplus triethylenetetramine 2 5 Ethylenediaminitetraacetic acid plusPluronie 13-62... 5 Ethylenediaminetetraacetic aeid plus Pluronie L-10132 5 (3H CH3 4 4s CrzHzg-CHC OzCHCHrK-O JJHCHTOR CHzCOzH TABLE I.Continued Percent separation, hrs. settling Percent Code Number cone.Structure 24 240 630-43B 2 N,N,N,N tetraethyl sebacamide 4 39 C E -CH00zCIICHz\O CHCHzl OR CHQG O NHCH2CII2 NH2 649-36-1 3 Reaction product oftetmpropenylsuccinic anhydride plus Ucon LB-385 3 1 19 649-35-1 5Reaction product tetraethylenepentamine plus Ucon LB-385 2 1 4 1 Soaplike deposit formed on graduate. 2 Sticky deposit formed. 3 at 72. 4 6at 72. 5 72 at 144. 96 at 120. 7 76 at 96. E 3 at 72.

The advantages of the ester addition compounds of EDTA and polyalkyleneglycol are immediately apparent from the foregoing table. Thesignificant advantage of these compounds as dispersant additives, ascompared with structurally related and similar compounds, is quiteunexpected. As an examination of the table will show, it is quiteimpossible to predict with any degree of certainty the potentialeffectiveness of a compound as a dispersant additive.

While we do not wish to be bound by the following reaction mechanism, itis believed, on the basis of infrared data, molecular weight, etc., thatthe following equation properly describes the reaction of the inventiveprocess. Side reactions of an undetermined nature are also believed tooccur, however.

Reaction scheme wherein R and R are hydrogen or lower alkyl and n is apositive integer from 1 to 100, e.g., in the specific exampleshereinbefore described.

Obviously, depending upon the reaction conditions, a mixture of mono,di, tri and tetrapolyalkylene glycol esters ofethylenediaminetetraacetic acid may be formed. The product of theaforementioned reactions comprises essentially an equilibrium mixture ofthese mono, di, tri and tetrapolyalkylene glycol-EDTA esters.

The lubricating compositions of this invention are preferably formed byblending the compounds heretofore described with end-blockedpolyalkylene glycol ether lubricating fluids, for example, theend-blocked polypropylene glycol ether identified as Ucon fluid DLB-200Eavailable from Union Carbide Plastics and Chemicals Department, NewYork. The dispersant additive concentration level 'is from 0.1 topercent generally, preferably from about 1 percent to about 25 percent,by weight. Oxidation inhibitors are also added inthe 0.1 percent to 5percent range, preferably in the range of from 0.5 percent to 3 percent.Many conventional oxidation inhibitors were tested and found to besuccessful, for example, 3 percent Oronite 254 is the preferred additivebut 1 percent concentration of 4,4-methylene, bis-2,6-ditertiary butylphenol (Ethyl 702), an alkylated phenol (Lubrizol 814), phenylalpha-naphthylamine, and

an alkylated diphenylamine (VanLube SL) were found to be successfuloxidation inhibiting additives.

U-con DLB-200 fluid is amber in color, has a viscosity at 210 F. of 58.3(SUS), at F. of 201 (SUS) and at 0 F. of 5660 (SUS). The viscosity, incentistokes, is 9.70 at 210 F., 43.2 at 100 F., 1230 at 0 F., 4140 at 20F. and 23,800 at 40 F. The viscosity index is 161, the pour point is -50F., the flash point is 520 F. and the fire point is 565 F. This productis described in Union Carbide Chemicals Company Advance TechnicalInformation publication 1 -40400, June 1959. Double end-blockedlubricants of this class generally may be used in the compositions ofthis invention, the primary consideration being the desired viscosityand viscosity index. The manufacture and properties of these compoundsis discussed by Gunderson et al., Synthetic Lubricants, Reinhold, NewYork, 1962, chapter 3 on Polyglycols. Reference is made to this work andthe publications and patents cited therein for a complete discussion ofthe lubricant base stocks used in the inventive composition.

It is diflicult to overestimate the importance of providing the properblend of lubricating fluid, dispersant additive, and oxidationinhibitor. To illustrate, using the fluids of the present invention,e.g., an end-blocked polyalkylene glycol ether lubricating base fluid, adispersant additive of the type described, and an oxidation inhibitor,e.g., Oronite 254, there is provided a potential lifetime motorlubricant. The lubricating properties of the base fluid are notdiminished under normal operating conditions; however, over long periodsof time the base fluid may be oxidized to form volatile components whichare discharged from the crankcase. An effective oxidation inhibitor is,therefore, necessary to prevent too rapid decomposition of the baselubricating fluid resulting in the necessity for continual addition oflubricant. Sludge is formed in every internal combustion engine fromcombustion products, wear products, etc. It is essential that thissludge be maintained in the lubricant and carried to an effectivefilter. Therefore, an effective dispersant additive is required toprovide an essentially homogeneous circulating lubricant fluid in whichthe sludge forming materials are maintained in dispersion. As thehomogeneous fluid is circulated through the oil filter, the sludgecomponents are removed and the clean lubricating fluid is returned tothe crankcase. Except for occasional addition of lubricating fluid, noadditional attention need be given to a vehicles engine lubricatingsystem. The convenience and economy of this type of fluid areimmediately apparent.

The lubricating compositions of this invention, the dispersantadditives, and the process for preparing these products have been setforth in rather specific terms to 7 aid those skilled in the art tounderstand and to practice the invention. Departures from the specificdisclosure will be made by those skilled in the art based upon theprinciples and teachings herein and such variations may be made withoutdeparting from the spirit and scope of the invention, as defined in thefollowing claims.

We claim:

1. A composition comprising a mixture of mono-, di-, tri-, andtetrapolyalkylene glycol esters of ethylenediaminetetraacetic acid.

2. A lubricant composition comprising a major portion of an end-blockedpolypropylene glycol diether and a minor portion of polyalkylcne glycolesters of ethylenediaminetetraacetic acid.

3. A mixed ester product prepared by reacting ethylenediaminetetraaceticacid with polyalkylene glycol monoether at temperatures in the range of75 C. to 300 C.

4. The product of the process of claim 3 wherein the 8 polyalkyleneglycol monoether is polypropylene glycol monoether of the formula mocmrhrr wherein R is lower alkyl and n is from 1 to 100.

References Cited UNITED STATES PATENTS 2/1962 Matson 252--5l.5A 2/1969Beavers et al. 260-482P

